Practical examples 85
Generator nominal power calculation
Generator values must be given at 50 Hz (60 Hz). These values are not equal to the wind
turbine nominal values. Wind turbine nominal power is achieved with 100% torque
reference at the nominal wind turbine speed.
Calculate the generator nominal power with the following equation.
Example:
Nominal operating point: Wind turbine nominal power is 1600 kW, wind turbine nominal
speed is 1770 rpm and generator nominal speed is 1511 rpm.
With 100% torque reference at 1770 rpm, the wind turbine output is 1600 kW, when
parameter 99.06 MOTOR NOM POWER value is
99.06 MOTOR NOM POWER = (1511 rpm
· 1600 kW) / 1770 rpm = 1365 kW.
Setting the equivalent circuit values to the parameters
When the equivalent circuit values are given for star connection and the rotor values are
reduced to the stator reference frame, the equivalent circuit values are set to the
parameters as shown in the table below.
Note: If the equivalent circuit values are given for delta connection, the values for
parameters 99.21 Rs, 99.22 X1S, 99.23 X2S, 99.24 XM and 99.25 Rr must be divided by
three.
X2 ’ and R
2
’
must be reduced to the stator reference frame. Reducing is marked with ‘
and it is calculated as shown below.
Parameter Equivalent circuit value Often marked as
99.21 Rs R
s
R
1
99.22 X1S X
s
×X1
99.23 X2S X
r
×Xr’
99.24 XM X
m
× X
h
99.25 Rr R
r
R
2
’
99.06 MOTOR NOM POWER
99.05 MOTOR NOM SPEED Wind turbine nom. power⋅
Wind turbine nom. speed
----------------------------------------------------------------------------------------------------------------------------------------------------=
2
=
99.25 Rr
R
2
99.15 MOTOR OPEN CKT V
99.02 MOTOR NOM VOLTAGE
2
99.15 MOTOR OPEN CKT V
99.02 MOTOR NOM VOLTAGE